Telephonic receiver



A. AND L. D. WILLIAMS.

TELEPHONIC RECEIVER. APPLICATION min MN. 2. 1911.

Patented Feb. 7, 1922.

w .m. m m 3 UNHTED sr TELEPHONIC RECEIVER.

Specification of Letters Patent.

Patented a 7,; 1922.

Application filed. January 12, 1917. Serial No.f142,009.

To all whomz't may concern Be it known that we, ALFRED VVILLIAMS and LEO DAFT WILLIAMS, both citizens of the United States of America, residing at 16 Hauteville Court Gardens, Stamford Brook, London, England, have invented a new and useful Improved Telephonic Receiver, of which the following is a specification.

This invention relates to an improved receiver of the thermophone type, and its object is to enable sounds, including the actual tones of the human voice, or of musical notes, to be plainly and clearly reproduced, and also to render audible electric impulses of any kind, especially those received from wireless transmitters.

It has already been proposed in connec-.

wires we use a bridge of metal foil or leaf preferably gold leaf suspended between supports and thereby we obtain great distinctness in articulatlon as well as other advantages.

Two methods of carrying out our invention are illustrated in the accompanying drawings.

Fig. 1 is an elevation of a single bridge of a simple form. A strip of metal foil F is attached by its ends to two conducting supports A,

Fig. 2 is a plan of the same.

Fig. 3 is an elevation of a multiple bridge. I

A, A are two conducting supports, B, B being insulated supports for the metal foil F, F. Where greater length of bridge is required the number of supporting pillars, such as B, may be increased. By placing them in suitable positions many may be put in a small space. V

Fig. 4 is an isometric elevation of a helical type of bridge. a, a are two conducting supports, corresponding with A, A in'the other figures, while the edges C of the body act as insulated supports correspondingto the pillars B.

The above represents only series working, but the bridge maybe connected in parallel or series-parallel according to the resistance desired.

The efiect of a parallel connection may be obtained in a single bridge by. using a greater width of metal leaf, but the efficacy of this depends on the strength of the currents available.

The thickness of the leaf used depends on the nature of the metal. We have found that any metal will work provided that the leaf employed can be beaten or rolled out thin enough. Alloys in the form of leaf or foil may be used. The results naturally vary with different kinds of metal leaf, and to get the best results with any particular metal leaf it is advisable to obtain the leaf as thin as possible consistent with its possessing the necessary mechanical strength for practical usage. Silver works very well, aluminum works well, and so does platinum,, but we have got the best results by using gold leaf of a thickness of approximatelf .0O000-35.000006 in. which is such that it transmits green light waves and by using gold leaf strips having a width of aboutone millimetre we have obtained a receiver which reproduces the human voice with remarkable fidelity; yet the bridge has ample mechanical strength to stand vibra- 7 of the order of gold leaf which transmits green light and means for supporting it at two points so as to hold the intermediate portion in suspension.

2. In a thermo-telephone receiver, a heating conductor of metal foil of a thickness of the order of gold leaf whichtransmits green light and means for supporting it means for supporting it at a plurality of points intermediate its ends.

In testimony whereof We have signed our names to this specification in the presence 15 of two subscribing Witnesses.

ALFRED WILLIAMS. LEO D. WILLIAMS.

Witnesses V KATHARINE ANNA WVILLrAMs MATILDA D. WILLIAMS.

Mam 

